Random thoughts

Bite sized information that has not yet made it into the blog yet,

Kernel Hacking

Raspberry Pi now uses Device Trees

18th July, 2015

The Raspberry Pi Foundation has recently introduced Device Trees as a mechanism for loading device drivers. This is to address the problem of multiple drivers contending for the same resources, and also to support automated configuration of the new HAT (Hardware Attached to Top?) compliant add-on modules.

If you building your own kernel, and are using a HAT compliant module, such as the IQaudIO DAC+, then you will need to configure the kernel with a valid trailer in order to enable Device Tree support.

If you do not do this then Raspbian will not load the required drivers – you will not see them under dmesg or via modprobe.